On Sun, Dec 14, 2014 at 09:47:26PM -0800, Linus Torvalds wrote: > and "save_xstate_sig+0x81" shows up on all stacks, although only on > CPU1 does it show up as a "guaranteed" part of the stack chain (ie it > matches frame pointer data too). CPU1 also has that __clear_user show > up (which is called from save_xstate_sig), but not other CPU's. CPU2 > and CPU3 have "save_xstate_sig+0x98" in addition to that +0x81 thing. > > My guess is that "save_xstate_sig+0x81" is the instruction after the > __clear_user call, and that CPU1 took the fault in __clear_user(), > while CPU2 and CPU3 took the fault at "save_xstate_sig+0x98" instead, > which I'd guess is the > > xsave64 (%rdi)
Err, maybe a wild guess, but could XSAVE be encountering some problems, like store ordering violations or somesuch? Quick search shows "AZ72. Store Ordering Violation When Using XSAVE" here http://download.intel.com/design/mobile/specupdt/320121.pdf which talks about SSE context stores happening out of order. Now, there are a lot of IFs like does Dave's machine even have the erratum and even if, would that erratum cause some sort of a livelock leading to the kernel lockups and so on and so on... It might be worth to rule out though. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
